Infrastructure

File store service (Google Drive)

• Stores spreadsheets
• Each launch store the survey in database. Delete the old one.

Spreadsheet service (Google Sheets)

• Stated spreadsheet that is a Template for all new surveys
  • (gets copied to a new spreadsheet when user ‘creates’ a new survey)
• Each ‘survey’ is represented by a single spreadsheet

Database (Postgres on Heroku)

• How is the survey stored on database tables?
  • DETAILS
  • Account: Login with google account
  • Survey: a Account could create many survey
  • Launch: if owner want to edit the survey, close the survey first and launch again after edited.
  • Page: different pages in a survey
  • Item: item is the question in different page in different survey
  • Response: each response is replied for each question(item)
• Database will only store the latest lauch of survey, not every version.
• We store not only the responses to each question, we also store a copy of the survey structure for each respondent
• Prototype Design Pattern
• Data Schema

Queuing (AWS SQS)

• situation: browser javascript POSTs submission to App; App writes to database
• problem: respondents submitting surveys caused heavy DB writes, which caused application to hang (> 50 writes per survey response) with hundreds of simultaneous submissions, even with Postgres multisert
• solution: browser javascript POSTs survey submission to App; App queues the submission information on AWS SQS; Background worker (shoryuken?) reads from SQS queue and systematically writes to DB.